The index was created by the U.S. travel platform BookRetreats together with Harvard‑affiliated psychiatrist Dr. Natalie Dattilo‑Ryan. It looks at 47 destinations around the world.

Instead of using opinions, the index measures five science‑backed factors: sunlight, quality sleep, a healthy diet, time spent in nature, and physical exercise. Each factor is given the same importance.

In Southeast Asia, Singapore is ranked 25th with a holiday happiness score of 49.8. The city‑state offers 66.20 sq.m of green space per person and enjoys 2,024 sunshine hours each year.

Kuala Lumpur comes in at 28th place with a score of 46.4. It provides 31.04 sq.m of green space per resident and receives 2,222 hours of sunshine annually.

Bangkok is placed 29th with a score of 45.7. The city has the region’s highest noise and light pollution rating of 59.11, but it still gets 2,624 sunshine hours each year.

Because the index uses measurable elements like sunlight and green space, travelers can compare destinations on concrete health benefits rather than just popular opinions. This helps people choose places that may improve their mood and well‑being while on holiday.